Network appliances are often used to provide access to one or more network services. A network appliance may comprise a number of virtual servers, each virtual server providing access to a number of services. The virtual servers may manage incoming connections from clients, and direct client requests to one or more services. In the course of managing incoming connection requests, network appliances may provide load balancing among the backend servers. When a virtual server is down or unavailable to service a connection request, the appliance may use a backup virtual server to manage incoming connections.
A virtual server may be operational but not operating at a desired performance level. A network appliance may direct a client request or connection to a virtual server which provides load balancing of a service available via multiple servers. If the service on each of the servers is down or unavailable, then the virtual server is not able to forward or load balance a request from a client. At that point, the network appliance may switch over to a backup virtual server providing access to and load balancing a second of set of servers to provide the service.